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Commit 94877768 authored by Jacob Keller's avatar Jacob Keller Committed by Jeff Kirsher
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fm10k: wait for queues to drain if stop_hw() fails once 



It turns out that sometimes during a reset the Tx queues will be
temporarily stuck longer than .stop_hw() expects. Work around this issue
by attempting to .stop_hw() first. If it tails, wait a number of
attempts until the Tx queues appear to be drained. After this, attempt
stop_hw() again. This ensures that we avoid waiting if we don't need to,
such as during the first initialization of a VF, and give the proper
amount of time necessary to recover from most situations. It is possible
that the hardware is actually stuck. For PFs, this is usually fixed by
a datapath reset. Unfortunately the VF cannot request a similar reset
for itself.

Signed-off-by: default avatarJacob Keller <jacob.e.keller@intel.com>
Tested-by: default avatarKrishneil Singh <Krishneil.k.singh@intel.com>
Signed-off-by: default avatarJeff Kirsher <jeffrey.t.kirsher@intel.com>
parent 106ca423

drivers/net/ethernet/intel/fm10k/fm10k.h

+1 −0
Original line number Diff line number Diff line
@@ -458,6 +458,7 @@ __be16 fm10k_tx_encap_offload(struct sk_buff *skb); 
netdev_tx_t fm10k_xmit_frame_ring(struct sk_buff *skb,

				  struct fm10k_ring *tx_ring);

void fm10k_tx_timeout_reset(struct fm10k_intfc *interface);

u64 fm10k_get_tx_pending(struct fm10k_ring *ring);

bool fm10k_check_tx_hang(struct fm10k_ring *tx_ring);

void fm10k_alloc_rx_buffers(struct fm10k_ring *rx_ring, u16 cleaned_count);

drivers/net/ethernet/intel/fm10k/fm10k_main.c

+1 −1
Original line number Diff line number Diff line
@@ -1128,7 +1128,7 @@ static u64 fm10k_get_tx_completed(struct fm10k_ring *ring) 
	return ring->stats.packets;

}



static u64 fm10k_get_tx_pending(struct fm10k_ring *ring)

u64 fm10k_get_tx_pending(struct fm10k_ring *ring)

{

	struct fm10k_intfc *interface = ring->q_vector->interface;

	struct fm10k_hw *hw = &interface->hw;

drivers/net/ethernet/intel/fm10k/fm10k_pci.c

+38 −6
Original line number Diff line number Diff line
@@ -1613,7 +1613,7 @@ void fm10k_down(struct fm10k_intfc *interface) 
{

	struct net_device *netdev = interface->netdev;

	struct fm10k_hw *hw = &interface->hw;

	int err;

	int err, i = 0, count = 0;



	/* signal that we are down to the interrupt handler and service task */

	if (test_and_set_bit(__FM10K_DOWN, &interface->state))
@@ -1629,9 +1629,6 @@ void fm10k_down(struct fm10k_intfc *interface) 
	/* reset Rx filters */

	fm10k_reset_rx_state(interface);



	/* allow 10ms for device to quiesce */

	usleep_range(10000, 20000);



	/* disable polling routines */

	fm10k_napi_disable_all(interface);
@@ -1642,10 +1639,45 @@ void fm10k_down(struct fm10k_intfc *interface) 
	while (test_and_set_bit(__FM10K_UPDATING_STATS, &interface->state))

		usleep_range(1000, 2000);



	/* skip waiting for TX DMA if we lost PCIe link */

	if (FM10K_REMOVED(hw->hw_addr))

		goto skip_tx_dma_drain;



	/* In some rare circumstances it can take a while for Tx queues to

	 * quiesce and be fully disabled. Attempt to .stop_hw() first, and

	 * then if we get ERR_REQUESTS_PENDING, go ahead and wait in a loop

	 * until the Tx queues have emptied, or until a number of retries. If

	 * we fail to clear within the retry loop, we will issue a warning

	 * indicating that Tx DMA is probably hung. Note this means we call

	 * .stop_hw() twice but this shouldn't cause any problems.

	 */

	err = hw->mac.ops.stop_hw(hw);

	if (err != FM10K_ERR_REQUESTS_PENDING)

		goto skip_tx_dma_drain;



#define TX_DMA_DRAIN_RETRIES 25

	for (count = 0; count < TX_DMA_DRAIN_RETRIES; count++) {

		usleep_range(10000, 20000);



		/* start checking at the last ring to have pending Tx */

		for (; i < interface->num_tx_queues; i++)

			if (fm10k_get_tx_pending(interface->tx_ring[i]))

				break;



		/* if all the queues are drained, we can break now */

		if (i == interface->num_tx_queues)

			break;

	}



	if (count >= TX_DMA_DRAIN_RETRIES)

		dev_err(&interface->pdev->dev,

			"Tx queues failed to drain after %d tries. Tx DMA is probably hung.\n",

			count);

skip_tx_dma_drain:

	/* Disable DMA engine for Tx/Rx */

	err = hw->mac.ops.stop_hw(hw);

	if (err == FM10K_ERR_REQUESTS_PENDING)

		dev_info(&interface->pdev->dev,

		dev_err(&interface->pdev->dev,

			"due to pending requests hw was not shut down gracefully\n");

	else if (err)

		dev_err(&interface->pdev->dev, "stop_hw failed: %d\n", err);